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A new receiver clock model to enhance BDS-3 real-time PPP time transfer with the PPP-B2b service

Satellite Navigation 2023年第1期4卷 1-12,I0002页

作者： Yulong Ge Qing Wang Yong Wang Daqian Lyu Xinyun Cao Fei Shen Xiaolin Meng School of Marine Science and Engineering Nanjing Normal UniversityNanjing 210023China School of Instrument Science and Engineering Southeast UniversityNanjing 211189China Jiangsu Province Institute of Surveying and Mapping Engineering Nanjing 210013China College of Electronic Engineering National University of Defense TechnologyHefei 230037China School of Geography Nanjing Normal UniversityNanjing 210023China Faculty of Architecture Civiland Transportation EngineeringBeijing University of TechnologyBeijing 100124China State Key Laboratory of Geodesy and Earth’s Dynamics Innovation Academy for Precision Measurement Science and TechnologyCASWuhan 430077China GNSS Research Center Wuhan UniversityWuhan 430079China

A new Precise Point Positioning(PPP)service,called the PPP-B2b service,has been implemented in the BeiDou-3 Navigation Satellite System(BDS-3),which brings new opportunities for time ***,the solution using the traditional PPP method with the PPP-B2b correction still absorbs some unknown errors and needs reconverging when there exist abnormal *** developed a new receiver clock model to improve PPP time transfer using the PPP-B2b *** traditional PPP time transfers using PPP-B2b with BDS-3,Global Positioning System(GPS),and BDS-3/GPS(Scheme1)are compared with the corresponding time transfer with the proposed clock model(Scheme2).The results show that GPS-only PPP is not recommended because of low accuracy of 2 ***-3 or BDS-3/GPS PPP time transfers in Scheme1 can realize about 0.2 ns *** the new clock model is applied,the accuracy can be improved by up to 45%and 39.8%for BDS-3 and BDS-3/GPS PPP,*** proposed clock model can signifcantly improve the short-term frequency stability by 57.4%,but less for the long-term stability.

关键词： PPP-B2b BDS-3 Time transfer Receiver clock model

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Research on Protection and Utilization Strategies of cultural Resources in Traditional Villages of Tourism Development 3

Research on Protection and Utilization Strategies of cultura...

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3rd International Conference on Energy Resources and Sustainable Development, ICERSD 2020

作者： Luo, Yiqing Wang, Donghua Wen, Haiqiao Civil Engineering and Architecture Jiangxi Science and Technology Normal University Nanchang Jiangxi330013 China

Pailou Village which is the hometown of Song Yingxing, who is the author of Tien-kung K'ai-wu, is taken as the research object in this paper. From the perspective of tourism development of traditional villages, the types of cultural resources in Pailou Village are summarized through combing the content of existing cultural resources. Then the value of its cultural resources is analyzed from three aspects: history and culture, art and society, tourism and economy. Therefore, the development path of the integration of culture and tourism is proposed, from five aspects of project positioning, industrial format, tourism planning, supporting facilities and smart tourism, the strategy of improving the tourism competitiveness of Pailou Village are summarized in this paper, which provides a theoretical reference for the sustainable development of traditional village tourism. © The Authors, published by EDP sciences 2021.

关键词： History

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A Novel Analysis Approach of Uniform Persistence for an Epidemic Model with Quarantine and Standard Incidence Rate

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 695-707页

作者： Song-bai GUO Yu-ling XUE Xi-liang LI Zuo-huan ZHENG School of Science Beijing University of Civil Engineering and ArchitectureBeijing 102616China School of Mathematics and Statistics Hainan Normal UniversityHaikou 571158China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China School of Mathematics and Information Science Shandong Technology and Business UniversityYantai 264005China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

Inspired by the transmission characteristics of the coronavirus disease 2019(COVID-19),an epidemic model with quarantine and standard incidence rate is first developed,then a novel analysis approach is proposed for finding the ultimate lower bound of the number of infected individuals,which means that the epidemic is uniformly persistent if the control reproduction number R_(c)>*** approach can be applied to the related biomat hem at ical models,and some existing works can be improved by using *** addition,the infection-free equilibrium V^(0)of the model is locally asymptotically stable(LAS)if R_(c)<1 and linearly stable if R_(c)=1;while V^(0)is unstable if R_(c)>1.

关键词： uniform persistence epidemic model control reproduction number quarantine standard incidence rate

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Numerical study of reactive pollutants diffusion in urban street canyons with a viaduct

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Building Simulation 2022年第7期15卷 1227-1241页

作者： Tingzhen Ming Cao Nie Wenyu Li Xin Kang Yongjia Wu Mengjie Zhang Chong Peng School of Civil Engineering and Architecture Wuhan University of TechnologyWuhan 430070China School of Architectural Engineering Huonggang Normal UniversityNo.146 Xingang Second RoadHuanggang 438000China Mechanical Engineering Department University of CaliforniaBerkeleyCA 94720USA School of Urban Planning and Architecture Huazhong University of Science and TechnologyWuhan 430074China

In this paper,the influences of the ambient wind speed and the height and width of a viaduct in a 2-dimensional street canyon on the diffusion of reactive pollutants emitted by motor vehicles were investigated using computational fluid dynamics(CFD)*** were treated as reactive by including a NO-NO_(2)-O_(3) photochemical reaction mechanism in the *** Reynolds-averaged Navier-Stokes(RANS)k-ε turbulence model and the discrete phase model were used to simulate the airflow movement and the concentration distribution,respectively,of the reactive pollutants in the street *** indices,i.e.,the chemical reaction contribution of NO(CRC_(NO)),the chemical reaction contribution of NO_(2)(CRC_(NO_(2))),and the O_(3) depletion rate,were used to evaluate the relative importance of the photochemical *** was found that the presence of a viaduct changed the flow field structure in the street *** CRC_(NO) and CRC_(NO_(2))decreased from the windward side to the leeward side of the *** maximum values of the CRC_(NO) and CRC_(NO_(2)) were observed at the pollution source(x=245 m)due to the influence of a clockwise vortex in the street *** the height and width of the viaduct increased,concentration of the ground pollutants and the O_(3) depletion rate *** O_(3) depletion rate was much higher on the leeward side(90%)than on the windward *** pollutant concentrations after the reaction were twice as high with the viaduct as without the viaduct when the viaduct height was the same as the building *** viaduct had a significantly larger influence on the concentration of the reactive pollutants than the chemical *** O_(3) depletion rate in the canyon and the pollutant concentrations decreased as the ambient wind speed increased,whereas the CRC_(NO_(2)) increased.

关键词： street canyon viaduct reactive pollutant-photochemical reaction CFD

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Cooling load characteristics of indoor spaces conditioned by decoupled radiant cooling unit with low radiant temperature

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Building Simulation 2022年第12期15卷 2067-2079页

作者： Yuying Liang Nan Zhang Huijun Wu Xinhua Xu Jianming Yang Gongsheng Huang Department of Architecture and Civil Engineering City University of Hong KongHong KongChina School of Civil Engineering Guangzhou UniversityGuangzhou 510006China Department of Building Environment&Energy Engineering Huazhong University of Science and TechnologyWuhanChina School of Automation Guangdong Polytechnic Normal UniversityGuangzhou 510665China

Decoupled radiant cooling units(DRCUs)are capable of increasing the cooling capacity without increasing condensation risks even using a much lower cooling temperature than conventional radiant cooling units(CRCUs).However,it is unclear whether DRCUs using low radiant cooling temperature will increase the cooling load of the conditioned indoor *** this study,the cooling load characteristics of a thermal chamber conditioned by a DRCU was investigated through developing a steady-state analysis model suitable for both DRCUs and *** total/radiative heat flux,as well as the heat exchange with a thermal manikin and walls were analysed under different surface temperatures of *** effect of the emissivity of the thermal chamber’external wall on the cooling load was also *** indicated that the cooling load under the DRCU was slightly smaller than that under the CRCU when the same operative environment was *** the infrared emissivity of the exterior wall’s inner surface could lead to a significant decrease in the cooling load for both the DRCU and *** decreasing the wall emissivity from 0.9 to 0.1,the total cooling load of the DRCU can be decreased by 8.4%and the heat gain of the exterior wall decreased by 21.6%.This study serves as a reference for developing the analysis model and understanding the load characteristics when DRCUs are used to create the thermal environment for indoor spaces.

关键词： radiant cooling condensation-free computational fluid dynamics cooling load hot and humid climates

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A reliability analysis framework coupled with statistical uncertainty characterization for geotechnical engineering

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Geoscience Frontiers 2024年第6期15卷 336-347页

作者： Liang Han Wengang Zhang Lin Wang Jia Fu Liang Xu Yu Wang School of Civil Engineering Suzhou University of Science and TechnologySuzhou 215011China School of Civil Engineering Chongqing UniversityChongqing 400045China Department of Architecture and Civil Engineering City University of Hong KongTat Chee AvenueKowloonHong KongChina School of National Safety and Emergency Management Beijing Normal UniversityZhuhai 519087China National Engineering Research Center of Gas Hydrate Exploration and Development Guangzhou Marine Geological SurveyGuangzhou 511458China College of Civil and Transportation Engineering Hohai UniversityNanjing 210024China Center of International Cooperation and Innovation for the Digital Economics Chongqing University of Posts and TelecommunicationsChongqing 400065China

Reliability analysis plays an important role in the risk management of geotechnical *** the random field-based method,it is expected that the uncertainty characterization of geo-material parameters and the realization of random field can be integrated ***,as the increase in measured data size is generally difficult in the field investigation of geotechnical engineering due to limitation of budget and time etc.,the statistical uncertainty resulting from sparse data should be paid great ***,taking the determination of hyper-parameters for Bayesian-based conditional random field as the breakthrough,this study proposed a reliability analysis framework to achieve the expectation *** this proposed reliability analysis framework,the present characterization method of statistical uncertainty is improved by setting the lognormal distribution as the prior distribution of scale of fluctuation(SOF).Subsequently,the performance of statistical uncertainty characterization method is tested by a set of unconfined compressive strength(UCS)database about ***,a case study about the stability analysis of slope is employed to demonstrate the beneficial effect of the proposed reliability analysis *** is found that the uncertainty in both the realization of random field and the reliability analysis results can be significantly mitigated by the proposed reliability analysis framework.

关键词： Reliability analysis Statistical uncertainty Bayesian inference Conditional random field Geotechnical engineering

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Research and Application of Urban 3D Modeling technology in Virtual Reality Scenes

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Applied Mathematics and Nonlinear sciences 2024年第1期9卷

作者： Ji, Hongfang Bao, Runbiao Zhang, Yimiao Department of Information Engineering Jiangxi Water Resources Institute Jiangxi Nanchang330010 China School of Civil Engineering Jiangxi Science and Technology Normal University Jiangxi Nanchang330010 China

In this paper, an automatic building extraction process based on MVS point clouds is proposed to automatically extract building point clouds from urban MVS dense point clouds of complex scenes by projection, morphological expansion and contour extraction techniques. Aiming at the deficiency of Poisson surface reconstruction, this paper proposes a surface model optimization method based on RANSAC fast fitting. The method generates the optimized surface model through the filter denoising process and chunked RANSAC fast fitting. Finally, a workflow for the 3D reconstruction of urban buildings based on the MVS point cloud is proposed. In the analysis for the urban 3D modeling technique, the average error of the model after reconstruction is only 0.731%, and the measurement errors in the three-dimensional directions of length, width, and height are less than 5 cm. and the time consumed before and after the optimized method in this paper is reduced by an average of 3.09 s. Therefore, this study provides a simple and efficient method for the automatic extraction and 3D reconstruction of urban buildings. © 2023 Hongfang Ji, Runbiao Bao and Yimiao Zhang, published by Sciendo.

关键词： 3D modeling

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Seismic Performance of Assembled Shear Wall with Defective Sleeve Connection

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Computer Modeling in engineering & sciences 2022年第4期131卷 199-217页

作者： Hua Yan Bo Song Dongsheng Xu Guodong Zhang School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China School of Architecture and Engineering Langfang Normal UniversityLangfang065000China Beijing International Science and Technology Cooperation Base for Earthquake Research on Mass Transit Railway Project Beijing100083China

In this paper,three kinds of shear walls with full sleeve grouting,fully defective sleeve and partially defective are designed for finite element analysis to analyze the influence of defects on the seismic performance of shear *** research shows that at the beginning of loading(5 s),the three models begin to appear compressive damage at the bottom of the wall in all three *** damage of the defect-free model develops rapidly,and the damage of the fully defective model is basically the same as that of the partially defective *** the gradual increase of displacement control(15 s),the compressive damages at the foot of the wall in the defect-free and partially defective grouting model are obvious,with plastic hinge formed in the foot of the wall,and the phenomenon of development along the pier body showing *** the structure is damaged,the overall compressive damages of the wall in the defect-free and partially defective models are obvious,and the damage on the defective side of the partially defective model is slightly *** the maximum stress of pre-stressed reinforcement in the defect-freemodel is concentrated at the top of the sleeve,themaximumstress of the pre-stressed steel bar in the fully defective model appears at the end of the steel bar in the *** hysteresis curve shape of the non-defectmodel and partially defective model are basically the same,showing a“shuttle”shape with a sound energy dissipation *** hysteresis curve shape of the fully defective model appears an obvious“pinch”*** yield displacement levels of the defect-free and partially defective models are smaller than that of the fully defective model *** stiffness degradation curves of the three models basically overlap with one *** the limit displacement,the stiffness results of the non-defect model and the partially defective model are greater than that of the fully defective *** the displacement is loaded to 20 mm,

关键词： Grouting sleeve defects shear wall finite element analysis seismic performance

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Performance analysis and improvement of air-cooled chiller system with enhanced heat rejection control 3

Performance analysis and improvement of air-cooled chiller s...

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3rd International Conference on Energy, Power and Electrical technology, ICEPET 2024

作者： Yang, Jia Shen, Changliang Fu, Ling Liu, Zhaoyong Chongqing University of Science and Technology School of Civil Engineering and Architecture Chongqing401331 China Chongqing Normal University Capital Construction Management Office Chongqing401331 China Chongqing Earthquake Agency Chongqing401147 China Chongqing College of Architecture and Technology Chongqing401331 China

ISBN: (纸本)9798350352658

The chiller system accounts for a significant proportion of a building's energy consumption. To improve the performance of air-cooled chillers, more energy-efficient condenser features were investigated in this study, including the variable speed condenser fans (VSCF) and the variable condensing temperature control (VCTC). The thermodynamic models by TRNSYS were developed for an air-cooled chiller with different heat rejection control, and the chiller performance with each heat rejection control was determined. In comparison with the conventional head pressure control (HPC), the chiller COP could be improved by 17.9% with VSCF under HPC, and it could be improved further by up to 51.8% with VSCF under VCTC. The chiller models were applied to determine how the different heat rejection control affected the energy consumption of air-cooled chillers serving an office building. The annual energy saving of the chillers with VSCF under VCTC was 7.7%, indicating the significant energy saving potential by using VSCF and VCTC for air-cooled chillers. © 2024 IEEE.

关键词： Energy efficiency

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Application of particle swarm optimization in multi-resource leveling optimization of engineering projects

Application of particle swarm optimization in multi-resource...

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作者： Tang Jian LAI Lu Architectural and Civil Engineering Institute Jiangxi Science and Technology Normal University

The purpose of this study is to use Particle Swarm 0ptimization(PSO)calculation to make the multiple resources in engineering projects reach global equilibrium after calculation. From the single-resource equilibrium optimization theory to the multi-resource optimization problem, the importance of engineering project resources is evaluated, appropriate evaluation indexes are selected, and a multi-resource equilibrium optimization mathematical model is established. Following that, the PSO solves the mathematical model, and the actual start time of activities(i.e., particle position) is constrained and rounded, subject to logical constraints between activities and time constraints. Finally, using the model to solve the case, the obtained results reduce the variance of resource intensity by 89.69% compared to the original solution, and the experimental results show that the PSO can effectively solve this kind of complex problem.

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